Internet porn is on the decline, and there’s nothing Paris Hilton can do about it.

That’s the conclusion of two separate reports by researchers studying traffic among millions of users and Websites across the globe. The shift is a major one for content filtering systems and company policies, which have spent most of the last decade focused on porn.

Earlier this week, Reuters published data from Bill Tancer, a self-described “data geek,” who has studied data from some 10 million Internet users and determined that social networking has dethroned pornography as the hottest attraction on the Web. Porn has dropped to about 10 percent of searches from 20 percent a decade ago, according to Tancer, who works for Hitwise, an Internet traffic monitoring company.

Next week, content filtering company Optenet will release its own report which helps to confirm Tancer’s findings. In a study of the full Internet — some 155 million Web pages — between 2006 and 2007, Optenet found that pornographic sites had dropped by nearly 9 percent in the space of a year.

The Optenet study, which counts and categorizes Websites across the Internet, found that porn still accounts for the largest number of Websites, registering more than 36 percent of the Web in 2007. Shopping sites, finished at No. 2 with 11 percent, followed by advertising and travel, which accounted for about 7 percent each.

The social networking trend does not appear in the Optenet study, likely because there still are relatively few such sites in the count.

There is significant growth in the number of objectionable sites that companies and service providers may want to filter or block, Optenet says. The report indicates that some of the fastest-growing categories of Websites are anonymizers, which multiplied by about 219 percent between 2006 and 2007; hacker sites (88 percent); and malicious code (70 percent).